RT Journal Article SR Electronic T1 The Importance of FDG-PET/CT in Multiple Myeloma JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP P360 OP P360 VO 64 IS supplement 1 A1 Gokhale, Saket A1 Kuang, Angie A1 Werner, Thomas A1 Revheim, Mona-Elisabeth A1 Alavi, Abass A1 Raynor, William YR 2023 UL http://jnm.snmjournals.org/content/64/supplement_1/P360.abstract AB P360 Introduction: 1. Discuss the utility of 18F-fluorodeoxyglucose (FDG)-PET/CT in the diagnosis of multiple myeloma. 2. Assess the ability of FDG-PET in monitoring the response to therapeutic interventions. 3. Assess the ability of dual time point (DTP) FDG-PET in differentiating benign from malignant lesions.Methods: PubMed, Google Scholar, and Web of Science were queried for primary literature examining the use of any somatostatin receptor targeting strategies in the diagnosis and/or therapeutic purpose. Searches were performed with the following terms: "FDG PET/CT", "multiple myeloma", "MM", "dual-time-point", "imaging", "diagnosis", and "therapy".Results: Multiple myeloma (MM) is a hematologic, plasma cell proliferative disorder of the bone marrow characterized by an abnormal number of plasma cells. Complications associated with MM include bone fractures, anemia, renal insufficiency, spinal cord compression, and immune dysfunction. With advances in effective treatment options for multiple myeloma (MM), many patients achieve complete response after first-line treatment. However, relapse is very common and this emphasizes the need for more sensitive imaging methods for accurate diagnosis and detection of minimal residual disease (MRD). Currently, the diagnosis and staging of MM can be assessed using traditional radiography, computed tomography (CT), and magnetic resonance imaging (MRI), which is the current gold standard for initial evaluation. However, FDG-PET/CT is recommended by the International Myeloma Working Group for patchy and extramedullary disease in MM. Furthermore, FDG-PET/CT can predict outcome, and a negative FDG-PET/CT has shown to be an independent predictor of survival. FDG-PET/CT in the evaluation of treatment effect can be performed much earlier than MRI, which lacks specificity. Thus, FDG-PET/CT is the recommended modality for treatment response evaluation.FDG-PET has been used in analyzing MM progression, chiefly early bone involvement and extramedullary disease. FDG-PET has proven to be capable of identifying more lesions compared to whole body radiographs. Disease progression can be identified by the development of new bony lesions or soft tissue involvement independent of serum monoclonal protein or light chain concentration. However, it is subject to high variability, with this great number of osteolytic lesions being a contributing factor. Thus, global assessment measured by FDG-PET has been shown to be a markedly straightforward yet dependable method to measure total disease activity by essentially analyzing gross metabolic changes. FDG-PET has also been shown to better effectively stage MM and detect lytic lesions compared to conventional imaging methods. In the Durie-Salmon Plus (DS Plus) staging system, FDG-PET information is utilized to accurately stage patients based on clinical factors including the quantity of lytic bone lesions, hemoglobin levels, and serum calcium. Additionally, DTP FDG-PET imaging has been useful in differentiating benign from malignant lesions, rendering it a useful tool to assess a patient’s response to chemotherapy for MM and allow for accurate assessment of the burden of disease. A challenge of this methodology is mainly limited sampling of diseased sites due to strict confinement of measured locations. Furthermore, volume based parameters associated with FDG-PET, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG) have promising applications in quantifying the burden of MM.Conclusions: FDG-PET has many promising applications in the diagnosis and monitoring of MM. It enables the detection of metabolically active plasma cells both inside and outside the bone marrow, thus directing therapy and assisting in prognostication. Furthermore, DTP FDG-PET has been shown to analyze treatment efficacy of MM, demonstrating the versatility of this imaging modality in regards to disease progression and treatment.